1. Field Of The Invention
This invention relates to an injection apparatus for introducing a fluid material into a molten metal bath and an associated method.
2. Description Of The Prior Art
While it has been known that the addition of reactive metallic elements such as lithium or sodium to a molten meta1 bath, particularly aluminum and aluminum based alloys may enhance the properties of the molten metal, attention must be directed toward safety considerations. Such reactive elements have a tendency to oxidize the alloy during processing and, as a result, can present a risk of explosion.
U.S. Pat. No. 4,248,630 discloses a method of making an aluminum alloy containing a highly reactive metallic element, such as lithium. The method uses a bath of molten aluminum where all of the alloying elements, except for the highly reactive metallic element are added initially to create an alloy melt. The alloy melt is degassed and the reactive metallic element is then added to the alloy melt by passing it through a transfer tube which is a metal shell lined with a refractory or other material resisting attack by the molten lithium. The transfer tube is provided with a suitable valve disposed therein.
There remains a need for an improved apparatus and method for introducing a fluid material, such as an alloying constituent and, more specifically, reactive metallic elements into a molten metal bath in an efficient manner under safe conditions.